QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

7km WSW of St. Helena, CA

· 8.3 km deep · released about 9.6 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Napa County 20 kmSonoma County 33 kmMarin County 52 kmSolano County 59 kmYolo County 60 kmLake County 71 kmColusa County 81 kmContra Costa County 82 kmSan Francisco County 95 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 1.7 (md)
Depth
8.3 km below the surface
Felt
no reports yet
Nearest
Napa County, 20 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1851 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 9.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 99× the energy of this one
  4. This earthquake M 1.7 about 9.6 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

Where

Epicentre 38.4882, -122.5492. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Napa County, CA 20 km (12 mi) W of here earthquakes near Napa County
Sonoma County, CA 33 km (21 mi) E of here earthquakes near Sonoma County
Marin County, CA 52 km (32 mi) NNE of here earthquakes near Marin County
Solano County, CA 59 km (36 mi) WNW of here earthquakes near Solano County
Yolo County, CA 60 km (37 mi) WSW of here earthquakes near Yolo County
Lake County, CA 71 km (44 mi) SSE of here earthquakes near Lake County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

56 earthquakes have been recorded within 50 km since this one.

  1. 1.7 3km SW of Anderson Springs, CA
  2. 2.6 3km NW of The Geysers, CA
  3. 1.6 10km NE of Healdsburg, CA
  4. 1.8 3km SE of Larkfield-Wikiup, CA
  5. 1.5 0km WNW of The Geysers, CA
  6. 2.0 9km WNW of The Geysers, CA
  7. 1.5 5km NW of The Geysers, CA
  8. 1.6 2km NW of Anderson Springs, CA
  9. 2.4 5km WNW of The Geysers, CA
  10. 1.8 3km ENE of The Geysers, CA
  11. 1.8 6km W of Allendale, CA
  12. 1.6 10km WNW of Calistoga, CA
  13. 2.5 5km NW of The Geysers, CA
  14. 1.7 6km WNW of Cobb, CA
  15. 2.3 6km W of Cobb, CA

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 5.0 on 2016-12-14 — it released about 100,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.